Songbird Migration

April and May are the months when the bulk of migratory songbirds make their way north to their breeding grounds. Most of these songbirds migrate in fall to areas south of the U.S., but some principally Canadian and/or montane breeders commonly winter in southern Florida in good numbers, such as Palm and Yellow-rumped Warblers. Our first definite northbound migrant warbler was an early Black-throated Blue Warbler on March 13, near Miami; our second was Hooded Warbler in central Georgia, a month later, on a more typical date of April 14. Since then, new migrating songbird species have been appearing regularly as we have traveled through South Carolina and northern Georgia. We’ve now seen 20 species of warblers this year in the East, out of about 38 possible.

From the Okefenokee Swamp, we headed north into east-central Georgia. Highlights in this area were: four species of carnivorous plants near Homerville, including beautiful stands of Yellow Pitcherplant, Sarracenia flava; the rare Silky Camelia, Stewartia malacodendron, in the Charles Harrold Preserve administered by The Nature Conservancy (TNC); and a flock of about 150 White Ibis foraging at close range in a dark swamp in General Coffee State Park (SP). But we soon were chased out of the region by a large storm system with high winds and tornado warnings. Using real-time radar we were able to dodge the worst of the weather, but we missed a couple locations we would have liked to visit. After quite a bit of research, we have settled on using a weather app called “Weather Timeline – Forecast” by Sam Ruston, available in Google Play Store, which uses forecasts from Dark Sky. The forecasts are quite accurate, and the app supports weather alerts, graphical displays of key parameters, and radar. Our version is ad-free, which I think cost a few dollars.

We spent ten days in South Carolina, starting at Congaree National Park (NP), which is particularly noted for its very tall floodplain forests, in which a number of tree species reach their greatest known size. One of the newer National Parks, converted from a National Monument in 2003, it has relatively limited visitor facilities: a visitor center; a few trails, including a superb multi-mile boardwalk; a small number of tent-camping sites; and Cedar Creek, which can be paddled in places, limited by downed trees. We spent one day hiking and one paddling, both very enjoyable, though we failed to find a target vascular plant family, probably because we were too early in the season. This was our 49^th U.S. national park; we still have three more that can be reached by vehicle (one each in Minnesota, Nevada, and Alaska). There are also three Canadian National Parks accessible by vehicle that we’ve not yet visited (one each in Quebec, Ontario, and Nova Scotia).

We camped in Poinsett SP, where each evening we listened to an extended Wood Thrush serenade; this species would surely make any birder’s top ten list of North American songsters, so the daily concerts were a great treat! While in the area, we also visited TNC’s lovely Peachtree Rock Heritage Preserve, outside Columbia, containing sandstone formations and the only waterfall in South Carolina’s Coastal Plain.

We next headed towards Charleston, searching for another new plant family. We found the target, Rustweed, Polypremum procumbens, without any difficulty; this is a widespread but not conspicuous species, and it has no close relatives (some botanists even place it in its own family, with no other species in the world). Two nights of camping in Francis Marion National Forest followed, with the day in between spent on a gorgeous 9-mile paddle on Wambah Creek. Several plants there were exciting new species for us, including the native wisteria vine, Wisteria frutescens, with large clusters of purple flowers; Blue Jasmine, Clematis crispa; and a white spider lily, Hymenocallis occidentalis.

We spent several days at Huntington Beach SP, visiting our friends Dick and Grace Wheeler in their nearby winter quarters, and enjoying the pristine beach, despite the very rainy weather. Painted Bunting, the most colorful bird in North America (red, lime green, and blue!), sang in the camping area during the rare lulls in the rain. Although it would have been nice to spend even more time along the coast, we did need to start heading west if we were going to explore the Ozark Mountains in Arkansas and Missouri before they got too hot.

 

So we headed inland, crossing the Fall Line and leaving the Coastal Plain for the first time since January. A fall line is the meeting of coastal sediments with an upland composed of consolidated bedrock. It is called a fall line because often there are waterfalls off the upland bedrock, onto the sediments. Rivers are often navigable from the coast up to the fall line, because the gradient of the coastal plain is so slight. The combination of the upstream end of navigability, with the availability of hydropower, makes rivers at the fall line an ideal location for settlement, and indeed many cities lie on the fall line running from New Jersey to Alabama, and separating the Coastal Plain from the Piedmont upland region.

Our first order of business in the Piedmont was to search for a nemesis vascular plant family, Podostemaceae, the riverweeds. There is just one species from this family in North America, and though it is fairly widespread in the East, it can be challenging to find. It grows submerged in swift-flowing waters, typically attached to rocks by sucker-like structures. We’d already looked for this species several times this year, but had been thwarted by high water levels and muddy water conditions, both from spring runoff. But where the Saluda River runs through Ware Shoals Park, in northwest South Carolina, we found Podostemum ceratophyllum to be common and easily accessible, by virtue of a large area of rocky shallows that can be waded with care. It was a thrill to finally encounter this species, which I had wanted to see since becoming particularly interested in aquatic plants in the mid-1990s!

We camped one night at Watson Mill Bridge SP in northeast Georgia, because there was a report of several bat species using the lovely covered bridge as a resting spot in between feeding bouts. That may have been an unusual event as it was associated with a huge insect emergence; we found only a single Little Brown Bat, with our thermal scope.

We used a day already compromised by heavy rain to get around Atlanta and reach northwest Georgia. There we visited two TNC preserves (Black’s Bluff and Marshall Forest) and Cloudland SP. The latter park has extremely scenic trails along the rim of, and down into, a sandstone canyon with some shale and limestone as well, and two high waterfalls. Mountain Rosebay (Rhododendron catawbiense) and occasional Mountain Laurel (Kalmia latifolia) provided gorgeous deep pink and white floral displays.

Next up: northern Alabama, an exceptionally interesting area botanically.